| A
curiosity at Labrador by R. E. Holttum |
| When
I was an undergraduate, I heard a great deal about Dipteris. I well
remember the occasion when Professor Seward, having visited Penang,
brought back to Cambridge with him a tall dried frond of this venerable
fern. And so when I came to Malaya, Dipteris was one of the few Malayan plants I knew something about. It is in fact one of those plants all botanists have heard about but few botanists have seen alive. The people |
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of Singapore are more fortunate; they have only to go to Labrador
cliff to inspect this remarkable plant. I want to explain why Dipteris is a botanical curiosity, why its presence in Singapore is of particular interest and has therefore led to the proposal that the plants on Labrador cliff should be preserved; and finally to suggest that not merely as a curiosity but in its own right as a plant of unique form and beauty it is worthy of respect and preservation. |
| Our Singapore Dipteris is the most widespread member of a small genus of ferns which occur in the Malayan region and eastwards to some of the islands of the Pacific. It shows an interesting combination of primitive characters with others more advanced and in this it agrees with certain fossil ferns which have been found in Jurassic rocks in Britain and in many other parts of the world. |  |
| It
is probable that the genus Dipteris, now restricted to a much smaller
area than its forebears, is a declining group of plants. Certainly
it is a descendent of an ancient race, which preserves some characters
of antiquity, and we have records of its fossil ancestors. For these
reasons, it is interesting to students of plant evolution. A Dipteris plant has a rather stout creeping rootstock covered with dark bristly hairs. This rootstock bears tall slender leaf-stalks, and on each of these is a large two-winged frond of curious form. Its prominent main veins are repeatedly forked, and the blade between them is supplied with an elaborate network of small veins. Few ferns have this type of branching of the main veins (which determines the shape of the frond) and still fewer combine this with an intervening network. The edges of the two halves of the frond are deeply lobed, and each half is shaped rather like a fan. All ferns show a certain precision of form, and symmetry of branching, which the leaves of flowering plants lack; Dipteris shows this symmetry in an unusual way, and has therefore a distinctive beauty of its own. Our species of Dipteris occurs abundantly in clearings in the forest on Penang Hill, but not below 2,000 feet elevation, and the same is true in other parts of Malaya where it grows.Why then should it grow at sea level in Singapore Island? Why also should it grow on Labrador cliff and two other sea cliffs on the island and not on the hills inland? |